Waveguide assembly



June 30., 1959 N. J. CEDRONE WAVEGUIDE ASSEMBLY Filed Feb. l8, 1955 INVENTOR.

NICHOLAS J. CEDRONE BY I i ATTORNEYS United States Patent 9 2,892,987 WAVEGUIDE ASSEMBLY Nicholas J. Cedrone, Needham Heights, Mass, assiguor to Metal Fabricators Corporation, Waitham, Mass., a corporation of Massachusetts Application February 18, 1955, Serial No. 489,129 2 Claims. (Cl. 333-98) The present invention relates to waveguides for conveying electromagnetic energy at high frequency, and is more particularly concerned with joints therefor.

One of the problems in the assembly of the waveguides is to provide for thermal expansion. For example, in the mounting of a waveguide for UHF television the waveguide is usually of aluminum and it runs alongside a steel tower. Owing to different degrees of expansion some provision for slippage is necessary. However, slip joints of customary design have frequently introduced discontinuities that affect the electrical characteristics.

The object of the present invention is to provide a joint for waveguides which is simple and inexpensive to construct and easy to install, which will allow for thermal expansion, and which introduces no significant discontinuities to affect the electrical properties of the waveguide.

With this object in view the present invention comprises certain novel features of construction and combinations and arrangement of parts hereinafter described and particularly defined in the claims.

In the accompanying drawings Fig. 1 is a sectional elevation of a portion of a waveguide embodying the joint of the present invention; and

Fig. 2 is a perspective view of a detail illustrating the construction at the corners of the guide.

The illustrated embodiment of the invention comprises a series of waveguide sections 4, each of any suitable cross-sectional shape, but shown here as rectangular. The main portions of the sections are fabricated in any suitable manner according to usual metal working techniques. The sections are preferably of aluminum in accordance with standard waveguide manufacturing practice.

Each section 4 is provided at its ends and around its entire periphery with coupling members. As shown in Fig. l the left-hand end of a section has a spring coupling device comprising a member 6 applied to each side of the rectangle. The member 6 comprises an angle member 3 to which is attached a series of spring fingers 10. Preferably the member 6 is a unitary structure, and to that end it is formed of extruded aluminum. The fingers are integral with the angle piece 8 and are separated into individual fingers by saw cuts. However, the member 6 may be fabricated from individual parts if desired.

The fingers 10 cooperate with coupling members on the opposed end of the next adjacent waveguide section. To this end, the right end of left-hand section 4, as shown in Fig. 1, is provided with four members 12, one for each side thereof, each member comprising an angle piece suitably secured to the end of the waveguide section. The angle pieces 12 are secured to the body of the waveguide, and protrude slightly beyond the end of the section, as indicated by the flange portion 13 in Fig. 1.

As shown in Fig. 1, the two sections are brought into nearly abutting relationship with the end of the righthand section received closely within the flange of the angle piece 12. The ends of the spring fingers 10 then grip the upper surfaces of the angle piece flanges 13, thereby securing the parts in place.

The angle pieces 6 and 12 may be secured to the waveguide sections in any suitable manner, as by brazing or spot welding. For rigidity, the end portions of the angle 2,892,987 Patented June 30, 1959 pieces are extended at the corners to permit welding at the joints indicated at 15 and 16 in Fig. 2.

As shown in Fig. 1, the sections 4 are not butted to gether, but a small gap is left between them to permit thermal expansion. A considerable degree of expansion or contraction is permitted since the right-hand section 4 may slide within the flange 13 of the angle piece 12.

From the foregoing it will be seen that the spring fingers 10 provide a firm compliant contact force around the entire periphery of the waveguide. This continuous contact is to be distinguished from joints in which the forces are applied only at intervals, as by means of bolts. The electrical characteristics of the guide are substantially unaffected as compared with a continuous guide in that the only discontinuity is the gap between the ends of the sections, and the gap is extremely small compared with the wavelength of the energy being transmitted, and there is no appreciable formation of standing waves which might impede the transmission. Any longitudinal currents required to flow through the guide pass from one section to the other through the horizontal flange portions 13, as indicated by the arrow in Fig. 1. No energy is required to flow through the springs 10.

As shown in the drawings, the members 6 and 12 are provided with suitable bolt holes 14 by which the outstanding flange portions of the angles may be attached to the tower or other supporting structure. On vertical runs it is contemplated that only one of the joint members of each section will be secured to the tower so that ample freedom for expansion is attained. If desired, longitudinal bolts may be connected between the members of each joint, but they should be loose enough to permit thermal expansion and contraction.

Having thus described the invention, I claim:

1. In a waveguide for conveying electromagnetic energy at high frequency, two rectangular waveguide sections, a plurality of angle pieces secured around the periphery of one of the sections and having flanges extending beyond the end of the section, the second section being received within said flanges and opposed to the end of the first section by a gap, and a plurality of coupling members secured around the periphery of the second section, each coupling member comprising a flange with integral spring fingers extending therefrom beyond the end of said second section and engaging the exterior surface of a flange of the first section to hold the outer end surface of the second section in engagement with the interior surface of said flanges.

2. In a waveguide for conveying electromagnetic energy at high frequency, two rectangular waveguide sections, a plurality of angle pieces secured around the periphery of one of the sections and having flanges extending beyond the end of the section, the second section being received within said flanges and opposed to the end of the first section by a gap, and a plurality of coupling members secured around the periphery of the second section, each coupling member comprising a unitary extruded member having a portion formed as an angle piece and a portion formed as a spring, said spring engaging the exterior surface of a flange of the first section to hold the outer end surface of the second section in engagement with the interior surface of said flanges.

References Cited in the file of this patent UNITED STATES PATENTS 1,043,683 Fieser Nov. 5, 1912 1,930,322 Paulson Oct. 10, 1933 2,305,668 Bruno Dec. 22, 1942 2,421,790 Korman June 10, 1947 2,513,067 Stephan June 27, 1950 2,656,515 Hansen Oct. 20, 1953 

